Cold treating machine



May 8, 19 1 R. E. BLU-DEAU ET AL CULD TREATING MACHINE Filed April 10, 1946 I I III/ElI/II/ 1 1/ I III! I IIIIIIIIII INVENTOR 5 ROBERT E. BLUDEAU JAMES H. BUG/(NAM ATTdRNEY Patented May 8, 1 951 COLD TREATING MACHINE Robert E. Bludeau, East Orange, and James H. Bucknam, Cranford, N. J assignors, by mesne assignments, to Union Carbide and Carbon Corporation, a corporation of New York Application April 10, 1946, Serial No. 661,029

This invention relates to the art of cold treating articles; particularly to a method and apparatus for cooling metal elements by precooling them in direct contact with a cold vapor prior to directly immersing them in a body of liquefied gas, such as liquid nitrogen, which latter vaporizes and provides the cold vapor for precooling the metal elements.

Liquefied gases, such as liquid air, liquid oxygen, and liquid nitrogen, have been used to cool metal elements to a very low temperature for various purposes; for example, to shrink the element for insertion in a recess in a machine memher to provide a permanent joint between the element and the member when the cold element warms to room temperature and expands.

Refrigerating metal articles by directly immersing them in a body of liquid oxygen is unsafe because of the serious explosion hazard involved; the grease or oil usually present on such articles oxidizes very rapidly in the presence of commercial pure oxygen. Also, the undiluted spent oxygen vapor, if allowed to escape into the atmosphere adjacent the cooling machine, may produce a concentration of oxygen around the machine that is dangerous to the attendants health.

The principal objects of this invention are; to provide equipment and procedure whereby metal articles can be efiiciently cooled to a very low temperature without incurring the hazards and dangers referred to above; to provide a cold treating machine in which the metal elements are more conveniently introduced and advanced through the machine to increase its rate of production; and to provide a cold treating machine which is simple and inexpensive to build and operate.

According to this invention, the articles to be cold treated, such as similar metal machine elements, are cooled by advancing them in succession through a body of liquid refrigerant, preferably liquid nitrogen, and then out of direct contact with the liquid into a delivery receptacle for use, e. g., for insertion in a recess in a machine member. Prior to their immersion and as they approach the body of the liquid refrigerant, the articles are precooled by directly contacting them with cold vapor given off by the vaporizable liquid refrigerant in which the precooled articles are subsequently immersed. Such precooling of the articles avoids the excessive vaporization of the liquid refrigerant which would occur upon immersing the articles at room temperature directly in the liquid refrigerant. The process is 10 Claims. (Cl. 62-1) 2 continuous in that there is no waiting period for the work to cool down to the desired temperature. The articles desirably are advanced intermittently along a guideway that extends from the article inlet of the machine through a cold vapor space directly communicating with the body of liquid refrigerant, then through and out of the body of liquid, and finally through the article discharge outlet. Suitable means, such as a reciprocable pusher, is operable to advance the articles along the guideway, and the machine inlet and outlet are normally closed by suitable means to reduce the loss of vaporized refrigerant.

Referring to the drawing:

The single figure of the drawing is a longitudinal section through a cold treating machine embodying this invention and operable to perform the improved article cooling method of the invention.

The refrigerating apparatus includes an outer casing or housing Ill. Where a number of rings such as those used for valve seats, are to be chilled such objects are fed through the top opening in the guideway II extending above the top of the casing, the guideway leading to a pusher operated by the handle I2 for moving the objects through a bath of liquid refrigerant and to the outlet end I3 of the guideway. A valve I4 closes the outlet I3 to conserve gas and cause a major portion of the vaporized liquid refrigerant to escape out the input side of the object guideway thereby exerting a precooling action upon the objects prior to their immersion in the liquid refrigerant.

A weight I5 of appropriate size is preferably though not necessarily attached to the valve I4 as illustrated. The valve is pivotally mounted as illustrated so as to be movable to the dotted line position. This valve is preferably automatically operated in response to one of the work pieces or rings rolling down the outlet end of the guideway. If desired the valve may instead be manually operated after the pusher handle I2 has been moved downward. Beneath the outlet I3 is a hopper IS in which the chilled object is retained so that the workman may pick it up and insert it in position in an engine block or wherever the work is to be used. For refilling the supply tank I9 with liquid refrigerant, a filling pipe I 'I is shown extending out of the top of the casing. A much larger pipe I8 also extends out of the casing for enabling irregular shaped pieces of work to be immersed directly or indirectly in the liquid refrigerant and cooled. The refrigerant tank I 9 is appropriately supported within the casing In as is accomplished by the supporting rods 2|] attached to the angle brackets 2| and passing under the tank I9 as illustrated. The portion of the guideway ll within thetank I9 is generally of U shape 22 as illustrated, the same being provided with perforations 23 where the guide passes through the liquid refrigerant. In order that the guide 22 may be supplied with vaporized refrigerant for precooling the incoming work, perforations 23 preferably extend above and below the liquid level in both sides of the guideway. On the left or input side of the guideway cold vaporized refrigerant may pass into and through the guide tube and out the upper or input end of the guideway ll, thereby precooling the objects 24 prior to their immersion in the liquid refrigerant. Downward movement of the handle i2 is transmitted to a plunger 25 which applies pressure to the line of objects within the guideway 22 pushing the objects down through the liquid refrigerant and causing one of them to roll down the outlet l3 opening the valve I4 and falling into the hopper IS. The gas space 26 above the liquid refrigerant need not be of any particular size. Thermal insulating material 21 fills the space between the outer casing If; and the liquid refrigerant tank I9. To minimize losses by heat conduction along them the supporting rods 20 are of a material which is not a good thermal conductor such as silicon bronze or stainless steel. Instead of the plunger 25 being manually operated, in installations where the rate of feed is high this plunger 25 may be operated by fluid pressure or electro magnetically in response to a push button or other manual operation. Such power operated plunger is desirable where the objects to be cooled are large.

Where the rate of consumption of the objects chilled is low, utilization of liquid refrigerant is at a low rate and the objects have time to become more nearly the temperature of the liquid refrigerant before they are immersed. On the other hand eificiency and utilization of the refrigerant is not usually a controlling factor but instead the need of the industry is important. Where the objects are used rapidly the degree of precooling of the objects before their immersion is smaller and the transfer of heat in the objects to the liquid refrigerant on immersion is high resulting in more rapid vaporization andalso in a greater amount of cold gas passing over. the objects for better precooling them.

Among the advantages of this invention may be mentioned the provision of a simple and inexpensive apparatus for chilling objects of uniform size. Where the diameter or length of the rings or other work pieces has changed a new size of guideway ii and 22 is needed. Unlike prior refrigerators using liquid oxygen this invention is simpler and when liquid nitrogen is the refrigerant the vaporized gas may safely escape directly into the atmosphere without being preheated or diluted. The herein disclosed method of cooling is adapted to be used for other purposes than where a shrink fit is desired, for example, the process could be used for bringing about a metallurigcal change such as aging, stress relieving, etc. Locating the plunger 25 and its operating handle i2 above the liquid level eliminates the necessity for using any packing or stuffing box where the same passes through the casing. The valve l4 conserves the loss of vaporized refrigerant out of the outlet I3 since when valve 24 is closed the gas is then directed up the input side of the guideway exerting a precooling action.

The fit of the reciprocating pusher 25 is loose enough to allow passage of the cold gas up the guideway 22 and out the top of the guideway II. The walls of the passageway l8 may not extend into the liquid. Where these walls l8 are metal they are preferably provided with a layer of thermal insulation 28 to reduce the conduction of heat from the outside to the walls of the liquid tank.

For cooling larger objects in the well 18 indirect cooling may be resorted to. For this purpose a removable tube, chamber, or cartridge 29 containing the objects to be cooled may be inserted and removed through the well opening. The walls of this cartridge or tube preferably protect the objects from direct contact with the liquid refrigerant and are of the same material as the guideways in order to reduce heat conduction between the outer casing and refrigerant. This cartridge is of the type adapted to slide within the walls of the well or guide tube l8 when the cover is removed. When such tube or cartridge is not being used in cooling the larger objects it should be removed. It will be understood this tube 29 is imperforate to protect the objects from direct contact with the liquid refrigerant. To provide for cooling objects within tube 29, vaporized refrigerant may be passed down the auxiliary passage 30 within the wall of tube 29 and across the bottom for discharge of cold gas in the central bottom portion of the tube 29 and over the objects therein. Perforations may be provided in the cover extending over tube I8. If desired a valve not shown may be placed at the top or input end of the guideway II for the purpose of conserving precooling gas, such a valve may be opened intermittently in response to the input of an object into the guideway or may be responsive to the existence of some predetermined low pressure in the guide- Way and tank. The walls of the guideways H and 22 being of stainless steel or of silicon bronze are relatively poor thermal conductors.

Additional guideways and additional well openings may be provided if desired for the same cooling apparatus. Where the door M is manually operated such may preferably be done by some Well known type treadle mechanism not shown. Instead of having the door l4 hinged at the top as illustrated it may also be hinged at the bottom to serve as a receiving tray for a chilled object. In'this latter event the door may close under the action of a spring around its hinge regardless of whether it automatically or manually actuates to open. For purposes of simplification the drawing does not show a liquid level gauge located on top of the outer casing and actuated in response to a float. A drain pipe not shown leads from the lower part of the refrigerant tank 19 to a valve outside the outer casing for draining the refrigerant. Liquid refrigerant should be drained from the tank is only when necessary, such as when a serious interruption occurs. Ordinarily liquid should not be drained from the tank for a work stoppage of short duration because to do so is both uneconomical and an unsafe practice. Also outside the casing may be provided a full liquid level trycock. Of course precautions are required in the drain pipe, etc. to prevent the transmission of heat between the refrigerant tank and outer casing.

One machine embodying the present invention +.000 O. D.1.635-.0005 Companion recessed mem- {+0005 ber I.D.-1.632.O 00

Valve insert Interference at room tem- {Max-0.0015" perature Min.-0.0005" Max. shrinkage of valve insert, at 320 F 0.0031" Approx. force necessary to separate assembled members 940 lbs.

We claim:

1. An apparatus comprising a liquid refrigerant tank, a guideway for objects being moved into and out of direct contact with a liquid refrigerant adapted to be received in said tank, a removable tube adapted to extend into the liquid refrigerant between the portions of said guideway extending into and out of the tank for cooling an object out of direct contact with the liquid refrigerant, and a passage for supplying vaporized refrigerant to an object in said tube.

2. Apparatus for cooling an object comprising a liquid refrigerant tank, a casing outside the tank, thermal insulating material between said tank and easing on at least some sides of the tank, a chamber in which an object to be cooled may be placed, a cover for said chamber outside the casing, and a passage for leading vaporized refrigerant from the tank above a liquid level into the bottom of said chamber, said passage leading downward within a side wall of said chamber.

3. In apparatus for cooling objects comprising a housing, a tank spaced from said housing on the inside, an object guide extending through said tank and housing, and a member adjacent the object input end of said guide for pushing objects one at a time into said guide and when the guide is filled the operation of said member forces an object out of the guide each time an object is pushed into said guide, the combination therewith of the improvement adapting said tank to retain a liquid refrigerant efliciently for cooling objects in said guide, said improvement including said tank being entirely within said housing to avoid thermal contact between any liquid refrigerant in said tank and the atmosphere outside said housing, said guide within said tank and above a liquid level being perforate to receive any vaporized refrigerant for contacting the same with objects therein, said guide entering and leaving said tank in an upper portion thereof to avoid liquid in the tank flowing out through said guide.

4. Apparatus according to claim 3 in which a closure is provided for an end portion of the guide, said closure being intermittently opened for movement of an'object past the same.

5. Apparatus according to claim 4 in which said intermittently movable closure is provided adjacent each end portion of the guide and outside said housing, said closure at the object input end of the guide being constituted by said object pushing member.

6. Apparatus according to claim 3 in which a tube extends through an upper portion of said housing and into said tank adjacent a lower portion thereof, said tube being provided with a passage leading from an upper portion of the tank into a lower portion of said tube, and a cover for said tube.

7. In apparatus for cooling objects comprising a housing, a tank spaced from said housing on the inside, thermal insulation between said housing and tank, a tube projecting into said tank and means for supplying vaporized refrigerant from an upper portion of said tank into said tube for cooling an object therein, the combination therewith of the improvement for reducing heat conduction along said tube, said improvement including said tube being of a material between the housing and tank to reduce heat conduction from the housing, and being removable through an upper portion of said tank and housing, and a guide for removal and insertion of said tube from and to said tank.

8. Apparatus according to claim '7 in which said means for supplying vaporized refrigerant to said tube is removable with said tube and carried thereby.

9. Apparatus according to claim 7 in which said means for supplying vaporized refrigerant from an upper portion of said tank delivers said vaporized refrigerant to a lower portion of said tube.

10. Apparatus according to claim 9 in which the circulation of vaporized refrigerant occurs automatically on insertion of said tube and in response to the vapor pressure in said tank being at least slightly superatmospheric and said vaporized refrigerant being discharged from said tube.

ROBERT E. BLUDEAU. JAMES H. BU CKNAM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,369,440 Jones Feb. 22, 1921 1,507,366 Britton Sept. 2, 1924 1,654,966 Draper Jan. 3, 1928 1,689,256 Sapp Oct. 30, 1928 1,940,164 Comer Dec. 19, 1933 1,940,192 Sorber Dec. 19, 1933 2,021,971 Varney Nov. 26, 1935 2,059,970 Robillard Nov. 3, 1936 2,445,294 Nelson July 13, 1948 2,487,821 McCandless et a1. Nov. 15, 1949 FOREIGN PATENTS Number Country Date 15,754 Great Britain Aug. 1. 1899 

